The Gumbel-softmax will choose a single location indicating the most important image region for the task. However, the searching space for the parameter of temperature is too large to be manually selected. And the temperature is a sensitive parameter as explained in [1]}. Hence in this paper we applied the adaptive temperature as in [2]}. The adaptive temperature is to determine the value of temperature adaptively depending on current hidden states. In other words, instead of being treated as pre-defined parameter, the value of temperature is learnt from data. Specifically, we can set the following mechanism to determine the temperature:
\(\tau = \frac{1}{Softplus(W_{temp} h_t^1+ b_{temp}) + 1}\) 
